New evidence found on how solar winds blow

The first data from NASA's new Sun-gazing satellite IRIS has revealed new evidence about how the heat of the sun travels through space.

Last year, NASA launched its Interface Region Imaging Spectrograph (IRIS) satellite to study ultraviolet light emissions from the Sun. It looks specifically at what is called the interface region, between the Sun's surface and its corona, a zone a few thousand kilometres deep where the energy from the Sun is converted into heat and radiation.

Now the first batch of data from the mission has been evaluated and scientists, publishing their work in the edition of Science published on Friday, said they have found evidence of intermittent, small-scale jets of hot gas travelling upward from the Sun's surface.

These findings reveal a region of the sun more complicated than previously thought.

Jeff Newmark, NASA

"Their speed is very high," said Astrophysicist Hui Tian from Harvard-Smithsonian Center for Astrophysics. "With an average of something like 260km per second, such high speeds have never been reported before in the region. They are moving outward from the interface regions of the solar atmosphere and to the higher layers of the solar atmosphere, or even to interplanetary space."

The discovery sheds light on how the energy from the Sun reaches Earth, and how the solar atmosphere is energised via what is known as solar winds.

"Solar wind is basically a string of ironised particles escaping from the solar atmosphere," said Tian. "Any perturbation in the physical conditions of the solar wind will lead to change in the upper atmosphere of Earth."

The high-energy electrons that make up the solar winds can have a significant impact when they reach Earth. More extreme solar flares - sudden bursts of light and energy from the sun - cause spectacular aurorae and can disrupt satellite, even damage power grids.

Identifying the smaller and weaker jets will help scientists better understand, even predict Earth's solar weather.

"If there is a dramatic change in the solar wind conditions then the physical conditions in the upper atmosphere of the Earth will also be changed," said Tian. "And the change of the physical conditions of the upper atmosphere will affect the performance of these satellites so services provided by these satellites like navigation will be seriously affected."

Data from IRIS has also revealed for the first time the existence of mini-tornadoes on the Sun's surface. It is believed these tornados and magnetic loops of plasma also seen for the first time, help transfer energy upward from the Sun into its much hotter corona.

"These findings reveal a region of the sun more complicated than previously thought," said Jeff Newmark from NASA.